This invention relates to a wastewater flocculating agent and its use in treating wastewater which contains an undesirable level of suspended organic materials. In a further aspect, the invention relates to a process for treating wastewater, such as is obtained in connection with polymerization processes and chemical compounding, with an organic non-polymeric cationic flocculating agent. Advantageously, the flocculating agent of the invention is biodegradable.
Large amounts of wastewater are generated in connection with the running of chemical plants where chemical compounding and latex polymerization processes, for example, are carried out on a daily basis. Such wastewater is loaded with suspended and dissolved organic materials including mixed polymer latex wastes and also including various ionic and non-ionic organic surfactants at solids concentrations typically ranging from 0.05 to 5 weight percent. Based on ecological considerations, disposal of such untreated wastewater by downstream dumping or draining in leach fields is undesirable and often restricted or prohibited by statute.
It is well known that treatment of turbid waters and such wastewaters described above involves precipitation and coagulation with subsequent flocculation whereby very minute particles and particles in colloidal form are coalesced into various dimensioned flocks which are thereafter separated by flotation, precipitation or sedimentation. A variety of processes are known for the primary treatment of such wastewaters. A representative process of the prior art comprises the precipitating, coagulation and flocculation of the solids therein by chemical means and thereafter subjecting the wastewater to a step of dissolved air flotation so as to float the sludge formed of the coagulated particles to the surface. The sludge is separated from the liquid by mechanical means and is thereafter buried while the treated wastewater is disposed of by spray irrigation in slow rate land treatment of leach fields. Alternatively, the flocculated sludge can be separated from the wastewater by know settling procedures. Lime, hydrated calcium oxide, in conjunction with ferric chloride; ferric sulfate, or alum is commonly used to precipitate and coagulate the contaminant suspended solids. In other processes, ferric chloride is used in conjunction with sodium hydroxide.
It is known that many wastewater treatment processes utilize polymeric flocculants comprising cationic, anionic and non-ionic polymers which are often added during the primary treatment of the wastewater to further aid in the flocculation of solids by lowering the charge of the contaminant particles as well as causing interparticle bridging, thereby increasing the size of the particle aggregates. Typically, a cationic polymer is added to the wastewater in amounts from about 50 to 800 ppm followed by the addition of an anionic polymer in amounts of from about 10 to 100 ppm.
A variety of wastewater treatment cationic polymers for enlarging and concentrating (compacting) the flocculated solids during the primary precipitation and coagulation is available commercially. Ordinarily such polymers are synthetic, high molecular weight polyelectrolytes, such, for example, as substituted polyacrylamide and polyquarternary amines. Commercially available cationic polymers include American Cyanamid 581C and 591C, and Primafloc C-3 supplied by Rohm and Haas. It is an advantage of the flocculating agents of the present invention that they promote flocculation of the wastewater suspended matter as effectively as the known conventional polymeric flocculating agents yet because of their non-polymeric fatty acid based chemical structure are biodegradable and also are less expensive than conventional, commercially available polymeric cationic flocculating agents.